I would suggest that you go to the following thread in the open discussion forum:

3 Attachment(s)Sticky: Membership? - **WARNING ** BEWARE** - Download p2p Clients ONLY Thru Official Sites ( 1 2 3 4 ... Last page )

Limewire doesn't charge for membership. It is a free program. Someone probably joined one of the scam sites like MyMusic.com or any number of the same type. It happened to me and I had to badger MyMusic.com horrendously but they did give me a refund. Or, you can contact your bank or credit card company. They don't take too kindly to internet fraud.

Good Luck.